2.1.5 Putting it together

"the expression below the line ... must have the static type ..."
    As in [Bug 1532], change "must have" to "has".

rule 3
    Italicize 'IntegerLiteral'.

"With this set of rules, we can compute the type of the expression above
in a bottom-up fashion"
    No, you can't, not bottom-up. Bottom-up implies that all information
    flows up, but you can't compute the type of the variable references
    in "($x,$x)" without the static environment information flowing down.

"The resulting type inference proceeds as follows."
    You should probably note that this uses a very ad hoc notation for
    (the values of) static environments.

"This example illustrates how each rule is applied ..."
    I don't think it illustrates it very well.
    -- The rules used at any stage are not identified.
    -- Only the 'has type' (colon) judgments appear.
       No 'of var expands to' judgments.
       No 'statEnv.varType() = ' judgments.
    -- The judgments that do appear are only in fully-instantiated forms,
       which makes it harder to relate them back to the judgments in the
       rules.
    -- The connections between rules, the way a premise of one rule
       relates to the conclusion of another rule, is not called out.
    -- Pattern-instantiation is very implicit.
    -- It ignores the intermediate ParenthesizedExpr.