diff --git a/src/doc/reference.md b/src/doc/reference.md index a7ed05c5a23..848c0df10ee 100644 --- a/src/doc/reference.md +++ b/src/doc/reference.md @@ -366,11 +366,19 @@ A _floating-point literal_ has one of two forms: optionally followed by another decimal literal, with an optional _exponent_. * A single _decimal literal_ followed by an _exponent_. -By default, a floating-point literal has a generic type, and, like integer -literals, the type must be uniquely determined from the context. There are two valid +Like integer literals, a floating-point literal may be followed by a +suffix, so long as the pre-suffix part does not end with `U+002E` (`.`). +The suffix forcibly sets the type of the literal. There are two valid _floating-point suffixes_, `f32` and `f64` (the 32-bit and 64-bit floating point types), which explicitly determine the type of the literal. +The type of an _unsuffixed_ floating-point literal is determined by type +inference. If a floating-point type can be _uniquely_ determined from the +surrounding program context, the unsuffixed floating-point literal has that type. +If the program context underconstrains the type, it defaults to double-precision `f64`; +if the program context overconstrains the type, it is considered a static type +error. + Examples of floating-point literals of various forms: ```